Specifies a Tcl command to associate with the button. This command
is typically invoked when mouse button 1 is released over the button
window. The button's global variable (-variable option) will
be updated before the command is invoked.

Specifies a desired height for the button.
If an image or bitmap is being displayed in the button then the value is in
screen units (i.e. any of the forms acceptable to Tk_GetPixels);
for text it is in lines of text.
If this option is not specified, the button's desired height is computed
from the size of the image or bitmap or text being displayed in it.

Specifies whether or not the indicator should be drawn. Must be a
proper boolean value. If false, the relief option is
ignored and the widget's relief is always sunken if the widget is
selected and raised otherwise.

Specifies the relief for the checkbutton when the indicator is not drawn and
the checkbutton is off. The default value is
“raised”.
By setting this option to
“flat”
and setting -indicatoron to false and -overrelief to
“raised”,
the effect is achieved
of having a flat button that raises on mouse-over and which is
depressed when activated. This is the behavior typically exhibited by
the Bold, Italic, and Underline checkbuttons on the toolbar of a
word-processor, for example.

Specifies an alternative relief for the checkbutton, to be used when the
mouse cursor is over the widget. This option can be used to make
toolbar buttons, by configuring -relief flat -overrelief
raised. If the value of this option is the empty string, then no
alternative relief is used when the mouse cursor is over the checkbutton.
The empty string is the default value.

Specifies a background color to use when the button is selected.
If indicatorOn is true then the color is used as the background for
the indicator regardless of the select state.
If indicatorOn is false, this color is used as the background
for the entire widget, in place of background or activeBackground,
whenever the widget is selected.
If specified as an empty string then no special color is used for
displaying when the widget is selected.

Specifies one of three states for the checkbutton: normal, active,
or disabled. In normal state the checkbutton is displayed using the
foreground and background options. The active state is
typically used when the pointer is over the checkbutton. In active state
the checkbutton is displayed using the activeForeground and
activeBackground options. Disabled state means that the checkbutton
should be insensitive: the default bindings will refuse to activate
the widget and will ignore mouse button presses.
In this state the disabledForeground and
background options determine how the checkbutton is displayed.

Specifies the name of a global variable to set to indicate whether
or not this button is selected. Defaults to the name of the
button within its parent (i.e. the last element of the button
window's path name).

Specifies a desired width for the button.
If an image or bitmap is being displayed in the button then the value is in
screen units (i.e. any of the forms acceptable to Tk_GetPixels);
for text it is in characters.
If this option is not specified, the button's desired width is computed
from the size of the image or bitmap or text being displayed in it.

The checkbutton command creates a new window (given by the
pathName argument) and makes it into a checkbutton widget.
Additional
options, described above, may be specified on the command line
or in the option database
to configure aspects of the checkbutton such as its colors, font,
text, and initial relief. The checkbutton command returns its
pathName argument. At the time this command is invoked,
there must not exist a window named pathName, but
pathName's parent must exist.

A checkbutton is a widget
that displays a textual string, bitmap or image
and a square called an indicator.
If text is displayed, it must all be in a single font, but it
can occupy multiple lines on the screen (if it contains newlines
or if wrapping occurs because of the wrapLength option) and
one of the characters may optionally be underlined using the
underline option.
A checkbutton has
all of the behavior of a simple button, including the
following: it can display itself in either of three different
ways, according to the state option;
it can be made to appear
raised, sunken, or flat; it can be made to flash; and it invokes
a Tcl command whenever mouse button 1 is clicked over the
checkbutton.

In addition, checkbuttons can be selected.
If a checkbutton is selected then the indicator is normally
drawn with a selected appearance, and
a Tcl variable associated with the checkbutton is set to a particular
value (normally 1).
The indicator is drawn with a check mark inside.
If the checkbutton is not selected, then the indicator is drawn with a
deselected appearance, and the associated variable is
set to a different value (typically 0).
The indicator is drawn without a check mark inside. In the special case
where the variable (if specified) has a value that matches the tristatevalue,
the indicator is drawn with a tri-state appearance and is in the tri-state
mode indicating mixed or multiple values. (This is used when the check
box represents the state of multiple items.)
The indicator is drawn in a platform dependent manner. Under Unix and
Windows, the background interior of the box is
“grayed”.
Under Mac, the indicator is drawn with a dash mark inside.
By default, the name of the variable associated with a checkbutton is the
same as the name used to create the checkbutton.
The variable name, and the
“on”,
“off”
and
“tristate”
values stored in it, may be modified with options on the command line
or in the option database.
Configuration options may also be used to modify the way the
indicator is displayed (or whether it is displayed at all).
By default a checkbutton is configured to select and deselect
itself on alternate button clicks.
In addition, each checkbutton monitors its associated variable and
automatically selects and deselects itself when the variables value
changes to and from the button's
“on”,
“off”
and
“tristate”
values.

Query or modify the configuration options of the widget.
If no option is specified, returns a list describing all of
the available options for pathName (see Tk_ConfigureInfo for
information on the format of this list). If option is specified
with no value, then the command returns a list describing the
one named option (this list will be identical to the corresponding
sublist of the value returned if no option is specified). If
one or more option-value pairs are specified, then the command
modifies the given widget option(s) to have the given value(s); in
this case the command returns an empty string.
Option may have any of the values accepted by the checkbutton
command.

Flashes the checkbutton. This is accomplished by redisplaying the checkbutton
several times, alternating between active and normal colors. At
the end of the flash the checkbutton is left in the same normal/active
state as when the command was invoked.
This command is ignored if the checkbutton's state is disabled.

Does just what would have happened if the user invoked the checkbutton
with the mouse: toggle the selection state of the button and invoke
the Tcl command associated with the checkbutton, if there is one.
The return value is the return value from the Tcl command, or an
empty string if there is no command associated with the checkbutton.
This command is ignored if the checkbutton's state is disabled.

Tk automatically creates class bindings for checkbuttons that give them
the following default behavior:

[1]

On Unix systems, a checkbutton activates whenever the mouse passes
over it and deactivates whenever the mouse leaves the checkbutton. On
Mac and Windows systems, when mouse button 1 is pressed over a
checkbutton, the button activates whenever the mouse pointer is inside
the button, and deactivates whenever the mouse pointer leaves the
button.

[2]

When mouse button 1 is pressed over a checkbutton, it is invoked (its
selection state toggles and the command associated with the button is
invoked, if there is one).

[3]

When a checkbutton has the input focus, the space key causes the checkbutton
to be invoked. Under Windows, there are additional key bindings; plus
(+) and equal (=) select the button, and minus (-) deselects the button.

If the checkbutton's state is disabled then none of the above
actions occur: the checkbutton is completely non-responsive.

The behavior of checkbuttons can be changed by defining new bindings for
individual widgets or by redefining the class bindings.